Railway signaling.



H. S- YOUNG.-

RAILWAY SIGN MING.

APPLICATION HLED DEC. 24. 1915.

mmfiw; Patented Mar. 26, 1918.

INVENTOR T T PATENT FFTQE.

HENRY S. YOUNG, OF WILKINSBURG, PENNSYLVANIA, ASSIGNOR TO THE UNIONSWITCH & SIGNAL COMPANY, OF SWISSVALE, PENNSYLVANIA, A CORPORATION OFPENNSYLVANIA.

RAILWAY SIGNALING.

Specification of Letters Patent.

Patented Mar. 26, 1918.

Application filed. December 24, 1915. Serial No. 68,490.

To all whom it may concern: 7

Be it known that I, HENRY S. YOUNG, a citizen of the United States,residing at Wilkinsburg, in the county of Allegheny and State ofPennsylvania, have invented certain new and useful Improvements inRailway Signaling, of which the following is a specification.

My invention relates to railway signal ing; more particularly it relatesto signaling for stretches of single track over which trafiic moves inboth directions.

I shall describe one form and arrangement of circuits and apparatusembodying my invention, and then point out the novel features thereof inclaims.

The accompanying drawing is a diagrammatic View showing a stretch ofrailway track having applied thereto one form of signaling systemembodying my invention.

Referring to the drawing, reference characters a and b designate thetrack rails of a railway track over which traffic moves in bothdirections. This track is divided into sections l-2 and 2-3 by insulatedjoints in the track rails at 1, 2 and 3, and each section is providedwith a track circuit. As here shown the track circuit for section 2-3comprises a track relay T connected to the rails a b by wires 11 and atransformer D, the secondary of which is connected to the rails by wires7 and the primary of which is connected to feeder wires 8 which aresupplied with signaling current from an alternator G. The track circuitof section 1-2 is here shown to be of the centerfed type and comprisestwo track relays T and T which are connected to the rails or and 6adjacent the ends of the section 1-2 by means of wires 12 and 13respectively. The source of current for this track circuit is atransformer B which is connected to the rails at the center of the tracksection by wires 14 and is supplied with electrical energy throughfeeders 8.

For governing traflic through section 1-2 from east to west, a signal Sis located adj acent the track rails at 1 and for governing traflicthrough the section in the opposite direction, a signal S is locatedadjacent the track rails at 2. These signals are governed respectivelyby relays R and R which are of a type responsive to reversals of currentin their energizing windings. As here shown each relay comprises twowindings c and "cl, and a rotor member f, winding d being constantlyenergized by current from a transformer located adjacent the relay.Winding (Z of relay R is connected in the following circuit: from oneterminal of transformer A, through wires 15, 1G and 17, winding cl ofrelay R and wire 18 to the other terminal of transformer A. Vinding clof relay R is similarly connected across transformer C. The windings cof relays R and R are connected in series with each other in thefollowing line circuit: from winding of relay R through wire 20. contact21 of relay T wire 22, contact 23 of relay T wire 24:, winding 0 ofrelay R wire 25, front contact 26 of relay T wire 27, the secondarywinding of a transformer N, wire 28, the secondary winding of atransformer M, wire 29, to winding 0 of relay R The primary windings oftransformers M and N in the above circuit are energized fromtransformers A and C respectively, being directly connected to thosetransformers as is evident from the drawing. The secondary oftransformer N is of higher potential than the secondary of transformer Mand is connected in the line circuit traced above in such manner thatits polarity is at every instant opposite'to the ptlarity of transformerM so that current flows in the line circuit in opposition to the voltageof transformer M. The windings 0 of relays R and R are connected in thiscircuit in such manner that when the current flows in the abovedirection, relay R is energized to hold its contact iinger 30 inengagement with its contact point whereas relay R is energized in thereverse direction so that its contact 31 is open. To reverse at timesthe current in the line circuit, I provide a branch around the secondaryof transformer N which branch comprises a wire 32 and the back contact26* of relay T \Vhen this relay is deenergized it first opens the linecircuit and disconnects transformer N from this circuit at front contact26 and immediately thereafter closes the line circuit at back contact 26leaving transformer N open at front contact 26. Transformer M is now theonly source of potential in the line circuit and the current whichpreviously flowed against the voltage of transformer M is now reversedto flow in the direction corresponding to the voltage of transformer M.The current in windings c of both relays R and R is therefore reversedso that the contacts of both relays are reversed, in other words,contact 30 of relay R is opened and contact 31 of relay R is closed. Iprefer to have the voltage of transformer N double the voltage oftransformer M because with this arrangement the currents in the linecircuit are of equal strength in either direction. For instance, iftransformer N has a voltage of 110 volts and transformer M has a voltageof 55 volts, the voltage in the line circuit when the two. transformersare in opposition is the difference between the two voltages or 55volts, which isnumerically equal but opposite in direction to thevoltage of transformer M alone. The voltages being equal and theimpedance of the line circuit being practically the same whether or notthe transformer N is connected in the circuit, the current in the linecircuit is the same in value no matter in which direction it is flowing.

The control of signals S and S by relays R and R is effected by circuitscontrolled by contacts 30 and 31 respectively. The circuit for thecontrol of signal S is, in detail, from transformer A, through wires 15and 34;, operating mechanism of signal S wire 35, contact 30 of relay R,wires 3-3 and 18 to transformer A. The circuit for the control of signalS is similar and. therefore need not be traced in detail.

The operation of this system of signaling is as follows: When there isno train in either section 1-2 or 2-3, all the track relays areenergized so that the line circuit is closed at contacts 21 and 23 ofrelays '1 and T respectively. Furthermore, transformer N is connected inthe line circuit at front contact 26 of relay T so that the current inthe line circuit flows in opposition to the voltage of transformer M,causing the contacts of relays R and R to be closed and openrespectively as indicated in the drawing. Signal S indicates proceedbecause its circuit is closed at contact 30 of relay R and. signal Sindicates stop because its circuit is open at contact 31 of relay R Whena west-bound train enters section 1-2 it deenergizes track relay T whichopens the line circuit at contact 21, so that windings 0 of both relaysR and R are deenergized. Consequently relay R opens its contact 30 sothat signal S assumes the stop position. Contact 31 of relay remains inthe open position, so that signal S' remains in the stop indication.With both signals S and S at stop both eastbound and westbound trafficis kept out of section 1-2 so that the train is protected both infrontand rear. As the train proceeds farther itdeenergizes track relay Twhich opens the line circuit at contact 23, but this has no effect onthe signals because the line circuit is already open at contact 21. Asthe train proceeds still farther, track relay T is re energized andcloses its front contact 21; again this has no immediate effect becausethe line circiut is now open at contact 23 of relay T \Vhen the trainenters section 2-3it deenergizes track relay T which opens'its' frontcontact 26and closes its back contact 26*, so that transformer N isdisconnected from the line circuit as hereinbefore ex plained.Thish'as-no immediate efiect on the signals because the line circuit isopen signal S at contact 31 so that signal S is,

brought to the proceed position in the rear of the train. 'lhisindication is useful in the event when it is desired to back thewestbound train into section 1-2.

When the train leaves section 2-3 completely track relay T isreenergized so that it closes its, front contact 26 and connectstransformer N into the line circuit with the result that the current inthe circuit is reversed. as hereinbefore explained. This causes relay Rto close contact 30 and relay R to open contact 31-, so that signal- Sassumes the proceed position and signal, S returns to the stop positionas shown in the drawing.

The operation of the apparatus for thepassage of a train in the reverse.direction, from west to east is as follows. When the train enterspreliminary section 2-3 it deenergizes track relay T which opens'itsront contact and closes. its back contact so that transformer N isshunted from the line circuit. As explained.hereinbefore, this causes areverse energization of both relays R and B so that the former openscontact 30 and the latter closes contact 31. As a consequence, signal Sis caused to go to the stop position to warnwestbound traflic not toenter section 1-2, whereas signal S assumes the proceed aspect givingthe eastbound train. the right to enter this section.

As the latter train proceeds into section 1-2, it short circuits trackrelay T W11Cl1 opens the line circuit at contact 23, so that windings 0of both relays R and R are deenergized. Relay R opens therefore thecircuit for signal S at its contact 31 so that signal S goes to the stopposition and prevents a following eastbound train from entering section12. As noted hereinbefore, contact 30 of relay R is already open so thatwhen relay R is deenergized signal S remains in the stop position. Thusthe train is fully protected while in section 1-2 there being a stopsignal at both ends of the section. As the train leaves preliminarysection 23 completely, track relay T 3 is reenergized so that it closesits front contact 26. As described hereinbefore, transformer N isthereby re-connected into the line circuit, but this has no immediateeffect because the line circuit is now open at contact 28 of track relayT As the train proceeds in stretch 1-2 it causes the denergization oftrack relay T which opens the line circuit at contact 21, but this hasno immediate effect on the signals because this circuit is open atcontact 23 of track relay T As the train proceeds still farther insection 12, track relay T is renergized and closes its contact 23. Thishas no efiect on the signals because the line circuit is now open atcontact 21 of track relay T As the train leaves section 1-2 completely,track relay T is reenergized and closes its contact 21 which completesthe line circuit. Because track relay T is also energized transformer Nis connected in the line circuit, as noted above, so that the directionof current through windings c of relays R and R is such that contact 30of relay R is closed whereas contact 31 of relay R is open, so thatsignal S indicates proceed whereas signal S indicates stop. In thismanner all the signals and other apparatus have been returned to thepositions wherein they are shown in the drawing.

One important feature of my invention is the immunity of the system fromfalse clear indications due to crossed line wires. I ac complish this byconnecting the signal controlling relays R and R in the line circuit insuch manner that it is necessary to operate either relay by current fromthe source at the opposite end of the circuit in order to energize therelay in such direction that the corresponding signal gives a proceedindication. This can be brought out more clearly by assuming forexample, that, while there is no train in either section 12 or 2-3, linewires 22 and 28 are crossed at point designated as in the drawing. Whenthis cross occurs the line circuit is divided into two local circuitseach having its source of current. transformer M, through wire 29,winding 0 of relay R wire 20, contact 21 of relay T wire 22, cross 00,and wire 28 to transformer M. The other of these circuits is similar andcomprises the other half of the line circuit with transformer N andwinding 0 of relay R The current in the former circuit flows inaccorcLnce with the direction of One of these circuits is: fromthevoltage of transformer M, so that relay R is energized reversely andopens contact 30, whereby signal S is immediately caused to change tothe stop indication. The current in the other local circuit flows inaccordance with the direction of the voltage of transformer N so thatrelay R remains energized reversely and signal S continues to indicatestop. Similarly, if a train occupies preliminary section 23 so thatsignal S indicates proceed and signal S indicates stop, a cross of theline wires causes signal S to change to the stop indication and signal Sto remain in the stop position.

Although I have herein shown and described only one form of circuitsembodying my invention, it is understood that various changes andmodifications may be made therein within the scope of the appendedclaims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In combination, a stretch of railway track, two signals located oneat each end of the stretch for governing traflic through the stretch inopposite directions, a line circuit comprising a source of energy forsending current through said circuit in one direction, a second sourceof energy stronger than said first source, means for at times connectingsaid second source into said circuit in Opposition to said first sourcefor reversin the direction of current in said circuit, and meansresponsive to the direction of current in said circuit for clearing oneor the other of said signals.

2. In combination, a section of railway track, two signals for governingtraffic through the section in opposite directions, a source of lowerpotential located at one end of the section, a source of higherpotential located at the other end of the section, a circuit comprisingsaid source of lower potential, means for at times connecting saidsource of higher potential into said circuit in opposition to saidsource of lower potential so that the direction of current in saidcircuit is reversed, and means responsive to the direction of current insaid circuit for clearing one or the other of said signals.

In combination, a section of railway track, two signals for governingtrafiic through the section in opposite directions, one signal beinglocated at each end of the section, a source of lower potential locatedat one end of the section, a source of higher potential located at theother end of the section, a relay responsive to reversals of current forthe control of each signal, a series circuit comprising said relays andsaid sources of potential connected in opposition so that currentnormally flows through said circuit in opposition to said source oflower potential, and means for at times cutting out said Source ofhigher potential from said circuit so that the direction of current insaid circuit is reversed.

-l- In COITlblllfllLlOll, a stretch of track divided into a main sectionand a preliminary section, signals located one adjacent each end of themain section for governing trai'fic therethrough in opposite directions,track circuits including track relays for said sections, a line circuitextending through said main section and controlled by the track relaysof said section, said circuit co1npris ing two sources of current onelocated adjacent each end of the track section, one of said sourcesbeing of higher potential than me err means responsive to thedirectionof current in said line circuit for clearing one or the other of saidsignals.

In testimony whereof I afiix my signature in presence of two Witnesses.1

HENRY S. YOUNG.

Witnesses A. L. VnNoILL, A. C. Nor/rm.

eplea at reheat may he obtained tor five-cents each, by addressing the"commissioner of Patents, Washington, I). G.

